Bottle cap having a first cap member and a second cap member assembled thereto

ABSTRACT

The bottle cap of the present invention consists of a first cap and a second cap fitted into the depressed portion of the first cap. The first cap includes a circumference portion formed so as to embrace the outer circumference of the neck of the bottle and a top edge portion formed on the top edge of said circumference portion so as to close the neck of the bottle. The top edge portion includes a depressed portion depressed downward so as to form a sidewall that comes into airtight contact with the inner circumference of the neck of the bottle. The second cap includes an insert portion inserted into the depressed portion and an elongated portion elongated outwardly from a top of the insert portion. Such a bottle cap provides an effect that sealability between the inside and outside of the neck of the bottle and the bottle cap can be improved.

TECHNICAL FIELD

The present invention relates to a bottle cap, and more specifically toa bottle cap for sealing the opening of bottle that accommodates liquidssuch as medical liquid, drinking water, liquor and other liquids.

BACKGROUND ART

Normally, bottle caps of various shapes are adopted as a means ofopening and closing bottles accommodating drinking water or fresh waterto prevent leakage or deterioration of the accommodated contents duringdistribution after input of the contents. Bottle caps that are generallydivided into a screw type bottle cap which uses an opening and closingmethod by screwing and an insert type bottle cap which uses an openingand closing method by insert means.

The screw type bottle cap is of a configuration in which a bottle caphaving internal threads formed on the inner circumference is assembledto the opening of bottle having external threads formed on the outercircumference. Therefore, sealability is high, so it is used as a bottlecap of the bottle for accommodating the contents requiring air tightnesssuch as carbonated beverages or beer. But such a bottle cap is of aconfiguration assembled to the external threads formed on the outercircumference of the bottle, so not only a considerable force is neededto open, but also the bottle cap should be turned repeatedly to open thebottle, so it has an inconvenience that it is difficult to open it atonce. Also, in the case that one has to use a bottle cap ofhigh-strength metal material such as iron or aluminum, there is aproblem that it takes much cost to manufacture the bottle cap andenvironment is destroyed due to extraction of iron material, etc.Another problem is that part of the bottle cap remains in the bottleafter opening the bottle cap, so extra breakaway work is needed for therecycling of the bottle, making separation work inconvenient forrecycling.

The insert type bottle cap is a configuration of fitting the bottle capinto the inner circumference of the neck of bottle, so it has anadvantage that it is easy to open and close the bottle cap. But such abottle cap is not only opened by a weak external force but also thesealability of the bottle cap is low, so it has a problem that it isdifficult to adopt it as the bottle cap of the bottle for accommodatingthe contents that require air tightness such as carbonated beverages orbeer, in particular.

DISCLOSURE OF INVENTION Technical Problem

In order to solve such problems as described above, the presentinvention has an object to provide a bottle cap, which has high enoughsealability to be adopted even for the bottle accommodating carbonatedbeverages, etc. and can be opened and closed by a simple action, and isenvironmentally friendly and low in manufacturing costs.

Technical Solution

To accomplish the object of the present invention, there is provided abottle cap installed in the opening of a bottle, comprising: a first capwhich includes a circumference portion formed in a cylindrical shape soas to embrace the outer circumference of a opening of a bottle, and atop edge portion having a depressed portion formed in downward recess soas to form a sidewall that comes into air-tight contact with the innercircumference of opening of the bottle; and a second cap which is fittedinto depressed portion of first cap. Therefore, the bottle cap of thepresent invention is formed in a dual structure so as to improve thesealability between the inside or outside of the opening of bottle andthe bottle cap.

In accordance with the present invention, the first cap has a firstcatch portion formed in one part of an inner sidewall of the depressedportion, and the second cap has a second catch portion formed in onepart of the outer circumference thereof to catch the first catchportion. Therefore, the fitting forces of the first cap and the secondcap are improved.

In accordance with the present invention, the second cap includes aninsert portion which is inserted into the depressed portion, and anelongated portion which is elongated outwardly from a top of the insertportion. And, the insert portion is provided with a support formedtherein to apply a lateral support force. the elongated portion has aprotrusion or slot for stripping formed on one part of the outercircumference. Preferably, the depressed portion of the first capincludes a stepped portion formed in stepped recess so that theelongated portion of the second cap is placed at the upper end of theinner sidewall. Therefore, It is easy to attach and detach between thefirst cap and the second cap.

In accordance with the present invention, the second cap is made of amaterial harder than that of the first cap. Therefore, the pressingforce of the second cap on the first cap is easily obtained.

In accordance with the present invention, the depressed portion of thefirst cap has the thickness of the sidewall formed thinner than theother portions in a predetermined portion. And, the portion where thethickness of the sidewall is formed thin is the lower section of thesidewall. Preferably, the sidewall of the depressed portion has itsinside depressed, so that its thickness is formed thin. Therefore, Thepressing force of the protruded portion on the inner wall of thedepressed portion is easily obtained.

In accordance with the present invention, the first cap includes acircular protrusion for breakaway prevention formed along the innersurface of the circumference portion. And, the first cap includes acircular slot for breakaway prevention formed along the inner surface ofthe circumference portion. Preferably, the first cap includes a circularprotrusion for sealing formed along the outer circumference of thesidewall. Therefore, Breakaway prevention and sealability of the firstcap for the opening of a bottle is improved.

In accordance with the present invention, a portion that connects thelower section of the depressed portion of the first cap and the bottomof thereof is curved. And, one or more of concave shaped air passages,which connect the lower section of the depressed portion and the bottomthereof, is formed on the outer surface so that air in the bottle can bedischarged when the bottle is opened. Preferably, each of the airpassages has the width of passage formed wider in the lower section ofthe depressed portion than in the bottom section thereof. Accordingly,when opening the first cap, the depressed portion is easily strippedfrom the inner circumference of the bottle opening. In addition, thesidewall includes a skirt portion elongated downward to the bottom endouter circumference section. Therefore, the sealability of the first capfor the bottle opening is improved.

In accordance with the present invention, the lower end of thecircumference portion of the first cap is depressed so as to be formedthinner than the other portion of the circumference portion. Therefore,Unintended stripping of the first cap by another member while carryingis prevented, and abnormal forced required for opening using a tool orfingernail is prevented.

In accordance with the present invention, the first cap further includesa plurality of tamper indication portions extended to the bottom endfrom the central portion of the circumference portion; a bended portionthat connects the upper ends of the plurality of tamper indicationportions in a line; an opening piece portion that is defined by theplurality of tamper indication portions and the bended portion; anopening knob that is protruded outward of the outer surface of theopening piece portion; and a supporting protrusion that is protrudedfrom a top of the bended portion so as to touch each other with the topedge of the opening knob of the opening piece portion when the openingpiece portion is moved upward by the breaking of the tamper indicationportions. Therefore, It is easy to open the first cap.

In accordance with the present invention, the tamper indication portionsis formed of breaking lines of a dotted-line type or cutting lines witha thickness thinner than the other portions. Therefore, it is easy tobreak the tamper indication portions.

In accordance with the present invention, the circumference portion iscut in such a way that the bottom end portion is curved upward in theportion where the opening knob is formed. Therefore, not only thesealability by the circumference portion is improved but also it is easyto operate the opening knob.

In accordance with the present invention, one or a plurality of breakinglines of a dotted-line type or cutting lines with thickness thinner thanthe other portions are formed along the upward and downward directionsof the circumference portion in the circumference portion on theopposite side of the portion where the opening knob is formed.Therefore, in the case of opening the bottle cap by the cut-and-openportion, it is easy to cut the circumference portion of the oppositeside, so it is easy to open the bottle cap.

ADVANTAGEOUS EFFECTS

Since the bottle cap of the present invention is formed in a dualstructure, it has an effect that sealability can be improved between theinside or outside of the opening of bottle and the bottle cap.

Also, the present invention improves the sealability of the bottle andprovides an effect that sealability can be maintained even at the timeof re-use after the bottle cap is opened.

In particular, the portion for connecting the lower end of the depressedportion of the first cap and the bottom thereof is formed in a curve, sothe bottle cap stripping work is easy.

A protrusion and slot for sealing are formed in the first cap and thesecond cap so as to improve the sealability of the bottle cap.

In addition, the present invention enables the bottle cap to be openedby simple action by dint of the cut-and-open portion and the bottle capis completely removed without part of it remaining on the bottle, soseparation work for recycling is easy.

BRIEF DESCRIPTION OF THE DRAWINGS

The above objects, features and advantages of the present invention willbecome more apparent to those skilled in the related art in conjunctionwith the accompanying drawings. In the drawings:

FIG. 1 is a perspective view showing a bottle cap according to a firstembodiment of the present invention;

FIG. 2 is an exploded perspective view showing a bottle cap according tothe first embodiment of the present invention;

FIG. 3 is a sectional view showing a bottle cap according to the firstembodiment of the present invention;

FIG. 4 and FIG. 5 are enlarged sectional views showing “A” portion ofFIG. 3;

FIG. 6 is a perspective view showing the bottom of the second cap of thebottle cap according to the first embodiment of the present invention;

FIG. 7 is a sectional view showing one example in which the bottle capaccording to the first embodiment of the present invention is installedin the bottle;

FIG. 8 is a sectional view showing another example in which the bottlecap according to the first embodiment of the present invention isinstalled in the bottle;

FIG. 9 is a schematic view showing an example of opening the bottle capaccording to the first embodiment of the present invention;

FIG. 10 is a perspective view showing a bottle cap according to a secondembodiment of the present invention;

FIG. 11 is an exploded perspective view showing the bottle cap accordingto the second embodiment of the present invention;

FIG. 12 is a sectional view showing the bottle cap according to thesecond embodiment of the present invention;

FIG. 13 is a sectional view showing one example in which the bottle capaccording to the second embodiment of the present invention isinstalled;

FIG. 14 is a sectional view showing another example in which the bottlecap according to the second embodiment of the present invention isinstalled;

FIGS. 15 to 19 are schematic views showing examples of opening bottlecaps according to the second embodiment of the present invention;

FIG. 20 is a bottom view showing a modified example of the bottle capaccording to the second embodiment of the present invention;

FIG. 21 is a sectional view showing a modified example of the bottle capaccording to the second embodiment of the present invention;

FIG. 22 is a detail view showing “B” portion of FIG. 21;

FIG. 23 is a bottom view showing another modified example of the bottlecap according to the second embodiment of the present invention;

FIG. 24 is a sectional view showing another modified example of thebottle cap according to the second embodiment of the present invention;

FIG. 25 is a detail view showing “C” portion of FIG. 24;

FIG. 26 is a sectional view showing a modified example of thecircumference portion of the first cap of the bottle cap according tothe second embodiment of the present invention;

FIG. 27 is a sectional view showing another modified example of thecircumference portion of the first cap of the bottle cap according tothe second embodiment of the present invention;

FIG. 28 is a side view showing a depressed portion formed on thecircumference portion of the bottle cap according to the secondembodiment of the present invention;

FIG. 29 is a sectional view showing a cutting line formed on thecircumference portion of the first cap of the bottle cap according tothe second embodiment of the present invention;

FIG. 30 is a bottom view showing the cutting line formed on thecircumference portion of the first cap of the bottle cap according tothe second embodiment of the present invention;

FIG. 31 is a schematic view showing the state in which the cutting lineon the circumference portion of the bottle cap of FIG. 29 is cut;

FIG. 32 is a sectional view showing another cutting line formed on thecircumference portion of the first cap of the bottle cap according tothe second embodiment of the present invention;

FIG. 33 is a bottom view showing another cutting line formed on thecircumference portion of the first cap of the bottle cap according tothe second embodiment of the present invention; and

FIG. 34 is a sectional view showing a fracture line formed on thecircumference portion of the first cap of the bottle cap according tothe second embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Below a bottle cap according to a preferred first embodiment of thepresent invention will be described in more detail with reference to theaccompanying drawings.

FIG. 1 is a perspective view showing a bottle cap according to a firstembodiment of the present invention, FIG. 2 is an exploded perspectiveview showing a bottle cap according to the first embodiment of thepresent invention, FIG. 3 is a sectional view showing a bottle capaccording to the first embodiment of the present invention, FIG. 4 andFIG. 5 are enlarged sectional views showing “A” portion of FIG. 3, andFIG. 6 is a perspective view showing the bottom of the second cap of thebottle cap according to the first embodiment of the present invention.

As shown in FIG. 1 and FIG. 2, the bottle cap according to the firstembodiment has a dual structure consisting of a cylindrical first cap 10and a circular second cap 20 to be inserted in the first cap 10. Such abottle cap closes the opening of a bottle 100 in close contact with theinner circumference and the outer circumference of the bottle 100.

The first cap 10 consists of a circumference portion 11, a top edgeportion 12 and a depressed portion 14.

The circumference portion 11 is formed in a cylindrical shape so as toembrace the outer circumference of the neck of the bottle 100, and onthe inner circumference 11 is formed a circular protrusion 16 forbreakaway prevention. The top edge portion 12 is formed on the top edgeof the circumference portion 11 so as to seal and close the top edge ofthe opening of the bottle 100. The depressed portion 14 is formed inrecess downward from the top edge portion 12 so as to form a sidewallthat is in air-tight contact with the inner circumference of the neck ofthe bottle 100.

At the upper end of the inner wall of the depressed portion 14 is formeda stepped portion 13. On one part of the inner wall of the depressedportion 14 is formed a first catch portion 15 of a protrusion shape.

As shown in FIGS. 3 to 6, on the lower surface of the depressed portion14 is formed a convex portion 18 that is protruded upwards. And on theinner surface near the lower portion of the sidewall forming thedepressed portion 14 is formed a concave portion 17.

On the depressed portion 14 are formed circular protrusions 14 a forsealing along the outer circumference of the sidewall. And the first cap10 is provided with a curved portion 14 b curved toward the portion thatconnects the lower end of the depressed portion 14 and the bottomthereof.

As material of the first cap 10, it is preferable to use soft resinsthat are easy to be deformed by pressing force, such as silicon rubber,polyvinyl chloride (PVC) and polyethylene (PE).

The circular second cap 20 is to be fitted in the depressed portion 14of the first cap 10 and has an insert portion 23 and an elongatedportion 21.

The insert portion 23 is formed in a barrel shape, and on one part ofthe insert portion 23 is formed a second catch portion 24 of aprotrusion shape. The insert portion 23 of the second cap is providedwith a support 23 a formed therein for improving the horizontal supportforce in the insert portion 23.

The elongated portion 21 of the second cap is formed in a circular rimshape to be elongated outwardly from the top of the insert portion 23,and on one part of the outer circumference of the elongated portion 21is formed a protrusion protruded downward or a recess 22 for strippingthe second cap. And the elongated portion 21 can be made in variousshapes such as star shape, hexagonal shape and octagonal shape besidesthe circular rim shape.

As material of the second cap 20, it is preferable to use hard resinssuch as polycarbonate, acrylic material, polyvinyl chloride (PVC) andpolyethylene (PE).

FIG. 7 is a sectional view showing one example in which the bottle capaccording to the first embodiment of the present invention is installedin the bottle.

As shown in FIG. 3 and FIG. 7, the first cap 10 is inserted to beassembled in the opening (i.e. neck) of the bottle 100 in close contactwith the inner circumference and the outer circumference thereof. Theinsert portion 23 of the second cap 20 is fitted to be assembled in thedepressed portion 14 of the first cap 10. The insert portion 23 is fixedin the depressed portion 14 by engaged fitting of the first catchportion 15 and the second catch portion 24. The circular protrusion 16for breakaway prevention formed along the inner surface of thecircumference portion 11 of the first cap 10 is assembled to the recessformed on the outer circumference of the neck of the bottle 100. Namely,the opening of the bottle is closed with the first cap 10 assembled tothe second cap 20.

With the insert portion 23 assembled like this in the depressed portion14, the inner wall of the depressed portion 14 is expanded outward.Accordingly, the insert portion 23 presses the depressed portion 14 soas to give a pressing force in an outwardly expanded direction, so thesealability between the inner circumference of the neck of the bottle100 and the depressed portion of the first cap 10 is improved.

Meanwhile, the support 23 a formed in the insert portion 23 has a shapein which two plates are arranged to cross each other in a raisedcondition so that the transverse cross section has a cross shape. Thissupport 23 a is molded monolithically with the second cap 20 when thesecond cap 20 is manufactured. This support 23 a has a function ofsupporting the insert portion 23 by resisting the contraction pressureagainst the insert portion 23 of the second cap 20, when the insertportion 23 of the second cap 20 receives contraction pressure by thedepressed portion 14 of the first cap 10 with the second cap 20 insertedinto the first cap 10. Accordingly, the inner support force of theinsert portion 23 is increased and the support force of outwardexpansion is also increased, so that the condition of applying lateralsupport force to the sidewall of the depressed portion is firmlymaintained. Such a support 23 a may be formed in various shapes so thatthe cross section has a cross shape, radial shape, honeycomb shape, etc.

Meanwhile, if pressing force is given upward by gas pressure ofcarbonated beverages, beer, etc. to the convex portion 18 of the firstcap 10, the convex portion 18 presses the sidewall of the depressedportion 14 from a bottom end to an upper side. At this time, thesidewall of the depressed portion 14 is not uniform in its thickness,and as illustrated in FIG. 3 and FIG. 4, the thickness is thinner in aspecific portion, namely, in the portion where the concave portion 17 isformed, than in the other portions. Accordingly, by the upward pressingforce applied to the sidewall of the depressed portion 14 through theconvex portion 18, the portion where the concave portion 17 is formed iscontracted, so the concave portion receives an outwardly protrudedforce, as shown in FIG. 5. As a result, the sidewall of the depressedportion 14 is expanded outwardly in the section where the concaveportion 17 is formed, so that it comes into close contact strongly withthe inner circumference of the neck of the bottle 100. Therefore, thesealability between the inner circumference of the neck of the bottle100 and the depressed portion of the first cap 10 is further improved.

The portion where the thickness of the sidewall of the depressed portion14 is formed thin is not limited to the lower section, and it is obviousthat it may be formed in the middle section of the sidewall or the upperend section of the sidewall. Also, the sidewall of the depressed portion14 may have the thickness of the sidewall formed thinner than the otherportions as the outer surface is depressed, but it is preferable thatthe inner surface of the sidewall is depressed so that the pressingforce applied by the convex portion 18 can be given outward of thesidewall.

And in the depressed portion 14 are formed circular protrusions 14 a forsealing along the outer circumference of the sidewall, so that thesealability between the inner circumference of the neck of the bottle100 and the depressed portion of the first cap 10 is improved. However,it is not necessary to form circular protrusions 14 a for sealing by allmeans. And one or more of the circular protrusions 14 a may be formed.

The circular protrusion 16 for breakaway prevention is assembled to therecess formed on the outer circumference of the neck of the bottle 100so as to prevent the first cap 10 from breaking away from the outercircumference of the neck of the bottle 100. The circular protrusion 16for breakaway prevention has also a function of improving thesealability of the outer circumference of the neck of the bottle 100 andthe inner circumference of the first cap 10. And the circular protrusion16 for breakaway prevention may have its cross section formed in variousshapes such as trapezoidal shape, semicircular shape and triangularshape, and makes stripping easy when opening the first cap 10.

It is preferable to make the second cap 20 with a material harder thanthat of the first cap 10 so that the first cap 10 is deformed easily bythe second cap 20. Accordingly, the insert portion 23 of hard materialis fitted into or stripped from the depressed portion 14 of softmaterial that is easy to be deformed, so the fitting and stripping ofthe second cap 20 into and from the first cap 10 are easy.

In addition, it is also possible to form the material and strength ofthe first cap 10 and the second cap 20 differently from each other forthe strengthening of sealability and the easiness of opening.

And in the case of stripping the insert portion 23 from the depressedportion 14, stripping work is easy if the protrusion or slot 22 forstripping formed on one side of the elongated portion 21 is used.Usually, stripping is done from the opening of the bottle 100 with thefirst cap 10 inclined, so friction force between the inner circumferenceof the neck of the bottle 100 and the depressed portion of the first cap10 is reduced by the curved portion 14 b of the first cap 10 so as tominimize the deformation of the first cap 10. Since the deformation ofthe first cap 10 is minimized when the first cap 10 is stripped, actionforce necessary for stripping work decreases to make stripping workeasy.

In the present embodiment, after assembling the first cap 10 to theopening of the bottle 100, the second cap 20 is assembled to the firstcap 10, but it is obvious that the first cap 10 is assembled to theopening of the bottle 100 after the second cap 20 is assembled to thefirst cap 10.

FIG. 8 is a sectional view showing another example in which a bottle capaccording to the first embodiment of the present invention is installed.

As shown in FIG. 8, a protrusion formed on the outer circumference ofthe neck of the bottle 100 is inserted in a circular recess 19 forbreakaway prevention formed along the inner surface of the circumferenceportion 11 of the first cap 10. Accordingly, breakaway of the first cap10 from the outer circumference of the neck of the bottle 100 isprevented. The circular recess 19 for breakaway prevention also has afunction of improving sealability between the outer circumference of theneck of the bottle 100 and the first cap 10. And it is preferable thatthe circular recess 19 for breakaway prevention has its cross sectionformed in various shapes such as a trapezoidal shape, semicircular shapeand triangular shape to make stripping easy when opening the first cap10.

To open the bottle cap of the present embodiment, the first cap 10 towhich the second cap 20 is assembled in the opening of the bottle isstripped obliquely upward to open the opening of the bottle.

And as shown in FIG. 9, since the first cap 10 and the second cap 20 areassembled to the opening of the bottle, it is also possible of course toopen the bottle by stripping the first cap 10 after stripping the secondcap 20 first.

Below a bottle cap according to a preferred second embodiment of thepresent invention will be described in more detail with reference to theaccompanying drawings.

FIG. 10 is a perspective view showing a bottle cap according to a secondembodiment of the present invention, FIG. 11 is an exploded perspectiveview showing the bottle cap according to the second embodiment of thepresent invention, FIG. 12 is a sectional view showing the bottle capaccording to the second embodiment of the present invention, FIG. 13 isa sectional view showing one example in which the bottle cap accordingto the second embodiment of the present invention is installed, and FIG.14 is a sectional view showing another example in which the bottle capaccording to the second embodiment of the present invention isinstalled.

The bottle cap of the present embodiment is identical with the bottlecap of the first embodiment described above except for the configurationin which a cut-and-open portion 30 is further provided. Accordingly, thesame numerals in drawings are given to the portions that are the samewith the first embodiment and the description thereof will be omitted.

As shown in FIGS. 10 to 14, the first cap 10 of the present embodimentis further provided on one part of the circumference portion 11 with acut-and-open portion 30 of the invention disclosed in InternationalPatent Application No. PCT/KR2004/002165 filed by the present inventor.

The cut-and-open portion 30 includes tamper indication portions 31, abended portion 32, an opening piece portion 33, an opening knob 34, anda supporting protrusion 35.

A plurality of the tamper indication portions 31 are formed extendingfrom the central portion to the bottom end of the circumference portion11. The bended portion 32 connects the upper ends of a plurality of thetamper indication portions 31 in a line. The opening piece portion 33 isdefined by a plurality of the tamper indication portions 31 and thebended portion 32. The opening knob 34 is formed in protrusion outwardof the outer surface of the opening piece portion.

The tamper indication portions 31 have a structure for confirmingwhether the bottle cap is opened for the first time, and it is formed ofa breaking line of dotted-line form or a cutting line with a thicknessthinner than the other portions so as to make breaking or cutting easywhen the opening piece portion 33 is moved upward.

The supporting protrusion 35 is formed in protrusion above the bendedportion 32 so as to touch each other with the top surface of the openingknob 34 of the opening piece portion 33 when the opening piece portion33 is moved upward by the breaking of the tamper indication portions 31.

When the user holds the bottom side of the bottle cap with one hand andtakes action of moving the bottom end of the opening piece portion 33upward with the thumb, etc., the opening piece portion is lifted up withthe axis on the bended portion 32 to break the tamper indicationportions 31. Next, the bottle cap is broken away from the opening of thebottle 100. Accordingly, it is possible for the user to open the firstcap 10 from the opening of the bottle 100 with one hand.

As shown in FIG. 13 and FIG. 14, like the aforementioned embodiment, thebottle cap of the present embodiment also has a circular protrusion 16for breakaway prevention or a circular recess 19 for breakawayprevention formed along the inner surface of the circumference portion11 of the first cap 10, so that it prevents the first cap 10 frombreaking away from the outer circumference of the neck of the bottle100.

Below the operation of the opening example of the bottle cap of thepresent embodiment will be described specifically with reference to theaccompanying drawings.

FIGS. 15 to 19 illustrate how the bottle caps according to the secondembodiment of the present invention are opened.

FIG. 15 illustrates how the first cap 10 and the second cap 20 arefitted into the opening of the bottle to seal the bottle. As shown inFIG. 16, the user places the end portion of his thumb on the openingknob 34 of the opening piece portion 33 to lift it upward. Then, asshown in FIG. 17, breaking occurs in the tamper indication portions 31.

As shown in FIG. 18, when the opening piece portion 33 and thesupporting protrusion 35 touch each other, the bottom portion of thethumb comes naturally into contact with the broken portion of theopening knob 34. Then, as shown in FIG. 19, the opening piece portionturns centering on the supporting protrusion while angular moment isgenerated on the whole of the bottle cap by dint of upward force due tothe thumb so as to open the opening of the bottle.

In particular, since a curved portion 14 b with a curve-shape is formedin the portion in the first cap 10 where the sidewall lower section ofthe depressed portion 14 is connected with the bottom surface thereof,the outer wall lower section of the depressed portion 14 can easily slipout of the opening of the bottle when the bottle cap is opened.

To open the bottle cap of the present embodiment, the cut-and-openportion 30 of the first cap 10 having the second cap 20 assembledthereto is used to strip the first cap upward obliquely from the openingof the bottle so as to have the opening of the bottle opened.

Also, since the first cap 10 is fitted in close contact with the openingof the bottle by the second cap 20, it is of course possible to open thebottle by stripping the first cap 10 from the opening of the bottleusing the cut-and-open portion 30 after stripping the second cap 20first.

FIGS. 20 to 22 illustrate modified examples of the bottle caps accordingto the embodiments illustrated in FIGS. 10 to 12. FIG. 20 is a bottomview showing an air passage 14 c formed in the first cap 10, and FIG. 21is a sectional view showing the air passage 14 c formed in the first cap10, and FIG. 22 is an enlarged view showing “B” portion of FIG. 21.

As shown in these drawings, on the outer surface of the curved portion14 b that connects the lower end of the depressed portion 14 and thebottom thereof is formed an air passage 14 c of a concave slot shapethat connects the lower end of the depressed portion 14 and the bottomthereof so that air inside the bottle can be discharged. As for such anair passage 14 c, one or more air passages having a uniform width ofpassage and formed in a straight line shape are arranged radially.

When the bottle cap is inclined in one direction in the process ofopening the bottle opening by the cut-and-open portion 30, the curvedportion 14 b comes into close contact with the inner circumference ofthe neck of the bottle to become in a sealed condition, as shown in FIG.19 mentioned above. With the curved portion 14 b in close contact withthe inner circumference of the neck of the bottle like this, if an airpassage 14 c as shown in FIGS. 20 to 22 is formed, carbon dioxide gasinside the bottle is discharged out through the air passage 14 c.

Thus, an opening sound is generated when carbon dioxide gas inside thebottle is discharged, and the user can feel the discharge of carbondioxide gas by their finger when it is discharged. Accordingly, the useris able to judge whether the bottle cap is opened or not, and at thesame time, he can know his opening is the first opening and also canhave a refreshing feeling by dint of the opening sound. And in the caseof beverages or beer containing carbon dioxide gas, the content couldoverflow at the time of initial opening, but since the inside air isslowly discharged by dint of such an air passage 14 c, overflow ofcontent can be prevented.

Since the bottle cap of the present embodiment is opened by thecut-and-open portion 30, the opening location of the bottle cap islimited to the location nearest to the cut-and-open portion 30.Therefore, the air inside the bottle is discharged out through the airpassage 14 c of this portion. So in the present embodiment, it would notmatter even if only one air passage 14 c is formed in the nearestlocation of the opening knob 34. However, if such an air passage 14 c isapplied to the bottle cap of the first embodiment, the opening locationof the bottle cap is not specifically limited but can be various, so itis preferable to arrange a plurality of air passages 14 c in the curvedportion 14 b in a radial shape.

In addition, as a modified example of the aforementioned air passage 14c, an enlarged type air passage 14 d, in which the width of air passageis formed wider in the lower section than in the bottom of the depressedportion, may be formed as shown in FIG. 23. In such a case of an airpassage 14 d, the upper portion of the air passage 14 d is expanded, sothat even in the case where the location of opening and the location ofair passage 14 d do not match accurately, discharge of the air in thebottle becomes possible by the expanded portion of the air passage 14 d.

Therefore, even in the case where the location of opening and thelocation of air passage 14 d do not match accurately, the opening soundis generated, so it is possible not only to check whether the bottle capwas opened initially or not, but also to feel freshness by dint of theopening sound and prevent overflow of the content. Especially if such anair passage 14 d is arranged radially in the curved portion 14 b, it ismore effective to apply the air passage 14 d to the bottle cap of thefirst embodiment.

FIG. 24 and FIG. 25 illustrate another modified example of the bottlecap according to the present embodiment. As shown in FIG. 24 and FIG.25, a downward elongated skirt portion 14 e is formed on thecircumference of the bottom end outer circumference section of thesidewall of the depressed portion 14. This skirt portion 14 e comes intoclose contact with the inner circumference of the neck of the bottle.Accordingly, when the gas pressure of the content such as carbonatedbeverages or beer in particular acts upward toward the opening of thebottle, the skirt portion 14 e is expanded outward by the pressure tocome into close contact with the inner circumference of the neck of thebottle 100. Therefore, the sealability between the inner circumferenceof the neck of the bottle 100 and the depressed portion 14 of the firstcap 10 is further improved. Such a skirt portion 14 e can be appliedalong with the modified example as shown in FIGS. 20 to 22, and can beapplied to the bottle cap of not only the second embodiment but also thefirst embodiment.

FIG. 26 and FIG. 27 are sectional views showing modified examples of thebottle cap circumference portion according to the present invention. Asshown in FIG. 26 and FIG. 27, the lower end of the circumference portion11 of the first cap 10 is depressed, so that it is formed thinner thanthe other portion of the circumference portion 11 with the thicknessdecreasing. For example, the lower end of the circumference portion 11is depressed, so it can be formed into a stepped portion 11 a as shownin FIG. 26, or into a curved portion 11 b as shown in FIG. 27.

Since the first cap 10 has the outside of the lower end of thecircumference portion 11 depressed, the bottle cap is not stripped butslipped even if the carriage box or a finger is caught on thecircumference portion 11 of the bottle cap 11 in the case that thebottle is transported or carried with the bottle cap not opened. Thecircumference of the bottom end portion depressed like this can preventunintended stripping of the bottle cap when the bottle is transported orcarried. Namely, the bottle cap having the depressed circumferenceportion 11 formed can be stripped only by opening the cut-and-openportion 30, so the function of preventing unintended breakaway of thebottle cap during transport or carrying is further improved.

Especially in the second embodiment of the present invention, the bottlecap is provided with the cut-and-open portion 30, so it is preferablethat the bottle cap is not opened by any other factor except the openingattempt by the cut-and-open portion 30. The circumference portion 11having the bottom section depressed like this plays a role of preventingthe bottle cap from being easily opened even during the opening attemptby an abnormal method using another tool or fingernail.

Such a depressed circumference portion 11 can be applied to the bottlecap of not only the second embodiment but also the first embodiment.

FIG. 28 is a side view of the bottle cap according to the secondembodiment, and for the sake of convenience of description andillustration, the cut-and-open portion 30 is shown with dotted lines. Asshown in FIG. 28, the circumference portion 11 of the first cap has adepressed portion 36 formed, in which the lower portion is cut to becurved upward in the portion where the opening knob 34 is formed.

In the bottle cap of the present embodiment, if the portion of thecircumference portion 11 where the opening knob 34 is formed is formedidentically with other circumference portion 11, the user's fingerinserting operation is not made from the state of FIG. 16 to the stateof FIG. 17 when opening the bottle cap but is caught by thecircumference portion 11 to make the opening operation inconvenient. Inorder to get rid of such a phenomenon that the finger is caught by thecircumference portion 11, a method of cutting out the portion of thecircumference portion 11 where the opening knob 34 is formed may beconsidered.

But if the portion of the circumference 11 where the opening knob 34 isformed is completely cut out, the operation of inserting a user's fingerinto the opening knob 34 is easy as shown in FIG. 17 and FIG. 18.However, in such a case the portion where the opening knob 34 of thecircumference portion 11 is formed is completely cut out, so sealabilityby the circumference portion 11 is lowered.

Therefore, by forming a depressed portion 36 in the portion of thecircumference 11 where the opening knob 34 is formed, the circumferenceportion 11 is partially cut out while the shape of the cut-out portionis made to match with the shape of the contact surface of the thumb thattouches during opening. Accordingly as shown in FIG. 17 and FIG. 18, theoperation of inserting the user's finger into the opening knob 34becomes easy, so that not only the opening operation for the openingknob 34 is easy but also the lowering of sealability due to thecircumference portion 11 is prevented.

FIGS. 29 to 34 illustrate cutting lines or breaking lines formed on thecircumference portion on the opposite side of the cut-and-open portionof the bottle cap according to the second embodiment.

As shown in FIG. 29 and FIG. 30, in the circumference portion 11 on theopposite side of the cut-and-open portion 30, namely, the circumferenceportion 11 on the opposite side of the portion of the circumference 11where the opening knob 34 is formed, is formed a cutting line 11 chaving the inner circumference cut out so as to have a thickness thinnerthan the other portions from the bottom end of the circumference portionupward to a predetermined length.

As shown in FIG. 31, when the user opens the bottle cap by pushingupward the cut-and-open portion 30, the circumference portion 11 on theopposite of the cut-and-open portion 30 is pressed downward to be cutupward from the bottom end along the cutting line 11 c. Accordingly,since the bottle cap is opened as the circumference portion 11 on theopposite side is cut out only by a small operation force against thecut-and-open portion 30, it becomes possible to open the bottle cap by asmaller operation force.

Also, such a cutting line 11 c has an advantage that it can play a roleas tamper indication portions because it is broken when the user opensthe bottle cap.

As shown in FIG. 32 and FIG. 33, as a modified example of theaforementioned cutting line 11 c, a cutting line 11 d can be formed onthe outer surface of the circumference portion 11 of the first cap.

In addition, as another modified example of such a cutting line, abreaking line 11 e, in which the bottom end is partially cut upward to apredetermined length and punched in a dotted-line form, can also beformed on the circumference portion 11 of the first cap as shown in FIG.34.

Such a breaking line 11 e has an advantage that it can give the feelingof being broken more clearly than the cutting lines when opening thebottle cap.

Only one of such a cutting line or breaking line was applied to thepresent embodiment, but it is also possible to apply by forming aplurality thereof according to the size or shape of the bottle cap.

As examples of such a plurality of cutting lines or breaking lines, thecase where one is formed in the center of the circumference portion 11and another one is formed respectively on both side portions and thecase where two are formed in a line in the center are possible.

INDUSTRIAL APPLICABILITY

The present invention can be used as a bottle cap which has high enoughsealability to be adopted in bottles accommodating carbonated beverages,can be opened by simple operation, is environmentally friendly and islow in manufacturing costs.

Although the present invention has been described in connection with theexemplary embodiments illustrated in the drawings, it is onlyillustrative. It will be understood by those skilled in the art thatvarious modifications and equivalents can be made to the presentinvention. Therefore, the true technical scope of the present inventionshould be defined by the appended claims.

1. A bottle cap installed in the opening of a bottle, comprising: afirst cap which includes a circumference portion formed in a cylindricalshape so as to embrace the outer circumference of a opening of a bottle,and a top edge portion having a depressed portion formed in downwardrecess so as to form a sidewall that comes into air-tight contact withthe inner circumference of said opening of the bottle; and a second capwhich is fitted into said depressed portion of said first cap.
 2. Thebottle cap of claim 1, wherein said first cap has a first catch portionformed in one part of an inner sidewall of said depressed portion, andsaid second cap has a second catch portion formed in one part of theouter circumference thereof to catch said first catch portion.
 3. Thebottle cap of claim 1, wherein said second cap includes an elongatedportion which is elongated outwardly from a top of said insert portion.4. The bottle cap of claim 3, wherein said insert portion is providedwith a support formed therein to apply a lateral support force.
 5. Thebottle cap of claim 3, wherein said elongated portion has a protrusionor slot for stripping formed on one part of the outer circumference. 6.The bottle cap of claim 3, wherein said depressed portion of said firstcap includes a stepped portion formed in stepped recess so that saidelongated portion of said second cap is placed at the upper end of theinner sidewall.
 7. (canceled)
 8. The bottle cap of claim 1, wherein saiddepressed portion of said first cap has the thickness of said sidewallformed thinner than the other portions in the lower section of saidsidewall.
 9. (canceled)
 10. The bottle cap of claim 8, wherein saidsidewall of said depressed portion has its inside depressed, so that itsthickness is formed thin.
 11. The bottle cap of claim 1, wherein saidfirst cap includes a circular protrusion for breakaway prevention formedalong the inner surface of said circumference portion.
 12. The bottlecap of claim 1, wherein said first cap includes a circular slot forbreakaway prevention formed along the inner surface of saidcircumference portion.
 13. The bottle cap of claim 1, wherein said firstcap includes a circular protrusion for sealing formed along the outercircumference of said sidewall.
 14. The bottle cap of claim 1, wherein aportion that connects the lower section of said depressed portion ofsaid first cap and the bottom of thereof is curved.
 15. The bottle capof claim 14, wherein one or more of concave shaped air passages, whichconnect the lower section of said depressed portion and the bottomthereof, is formed on the outer surface so that air in the bottle can bedischarged when the bottle is opened.
 16. The bottle cap of claim 15,wherein each of said air passages has the width of passage formed widerin the lower section of said depressed portion than in the bottomsection thereof.
 17. The bottle cap of claim 14, wherein said sidewallincludes a skirt portion elongated downward to the bottom end outercircumference section.
 18. The bottle cap of claim 1, wherein the lowerend of said circumference portion of said first cap is depressed so asto be formed thinner than the other portion of said circumferenceportion.
 19. The bottle cap of any one of claims 1, wherein said firstcap further includes a plurality of tamper indication portions extendedto the bottom end from the central portion of said circumferenceportion; a bended portion that connects the upper ends of said pluralityof tamper indication portions in a line; an opening piece portion thatis defined by said plurality of tamper indication portions and saidbended portion; an opening knob that is protruded outward of the outersurface of said opening piece portion; and a supporting protrusion thatis protruded from a top of said bended portion so as to touch each otherwith the top edge of the opening knob of the opening piece portion whensaid opening piece portion is moved upward by the breaking of saidtamper indication portions.
 20. The bottle cap of claim 19, wherein saidtamper indication portions is formed of breaking lines of a dotted-linetype or cutting lines with a thickness thinner than the other portions.21. The bottle cap of claim 19, wherein said circumference portion iscut in such a way that the bottom end portion is curved upward in theportion where said opening knob is formed.
 22. The bottle cap of claim19, wherein one or a plurality of breaking lines of a dotted-line typeor cutting lines with thickness thinner than the other portions areformed along the upward and downward directions of said circumferenceportion in the circumference portion on the opposite side of the portionwhere said opening knob is formed.